chxavcommand.h

来自「symbian 下的helix player源代码」· C头文件 代码 · 共 268 行

/************************************************************************
 * chxavcommand.h
 * --------------
 *
 * Synopsis:
 * abstract interface for command objects, CHXAvCommand
 * concrete wrappers for calls to class member function:
 *	no-arg class member function object 
 *	one-arg class member function object
 *
 *  Example:
 *
 *  class Music
 *  {
 *  public:
 *	void SetEventAction(EventType type, const CHXAvCommand& cmd);
 *	...
 *  };
 *
 *  class Dancer
 *  { ... };
 *
 *  void DoBreakDance() {...} // no args
 *  void Bow(TInt count) {...} // one arg
 *
 *  void Dancer::Init(Music* pMusic)
 *  {
 *	//
 *	// start break dancing when music begins,
 *	// bow three times when music ends
 *	//
 *	const CHXAvCommand& cmdStart = MakeCommand(this, &Dancer::DoBreakDance);
 *	const CHXAvCommand& cmdEnd = MakeCommand(this, &Dancer::Bow, 3);
 *	pMusic->SetEventAction(Music::OnBegin, cmdStart);
 *	pMusic->SetEventAction(Music::OnEnd, cmdEnd);
 *  }
 *
 * 
 * Target:
 * Symbian OS
 *
 *
 * (c) 1995-2003 RealNetworks, Inc. Patents pending. All rights reserved.
 *
 ************************************************************************/
#ifndef _chxavcommand_h_
#define _chxavcommand_h_

// Includes from this project...
#include "chxavrefptr.h"


//
// class CHXAvCommand_
//
// command base class
template<typename ReturnType>
class CHXAvCommand_ 
{
public:
    virtual ReturnType Execute() = 0;
    virtual CHXAvCommand_* CloneL() const = 0;
    virtual ~CHXAvCommand_() {};
};

// class CHXAvCommand
typedef CHXAvCommand_<void> CHXAvCommand;
typedef refptr<CHXAvCommand> CHXAvCommandPtr;

// class CHXAvBoolCommand
typedef CHXAvCommand_<bool> CHXAvBoolCommand;
typedef refptr<CHXAvBoolCommand> CHXAvBoolCommandPtr;


//
// class CHXAvCommand0_
//
// call to member func that takes no args, has a return val
template< typename ClassType, typename ReturnType >
class CHXAvCommand0_ : public CHXAvCommand_<ReturnType>
{
public:
    typedef ReturnType (ClassType::*PCMFN)();

    CHXAvCommand0_(ClassType* pObject, PCMFN pMethod) : m_pObject(pObject), m_pMethod(pMethod) {}
    ReturnType Execute()
    {
        return (m_pObject->*m_pMethod)();
    }
    CHXAvCommand_<ReturnType>* CloneL() const 
    {
        return new (ELeave) CHXAvCommand0_(*this);
    }
private:
    ClassType* m_pObject;
    PCMFN m_pMethod;
};

//
// class CHXAvCommand1_
//
// call to member func that takes one arg, has a return val
template< typename ClassType, typename ReturnType, typename ArgType >
class CHXAvCommand1_ : public CHXAvCommand_<ReturnType>
{
public:
    typedef ReturnType (ClassType::*PCMFN)(ArgType arg);

    CHXAvCommand1_(ClassType* pObject, PCMFN pMethod, ArgType arg) 
	    : m_pObject(pObject), m_pMethod(pMethod), m_arg(arg) {}
    ReturnType Execute()
    {
        return (m_pObject->*m_pMethod)(m_arg);
    }
    CHXAvCommand_<ReturnType>* CloneL() const
    {
        return new (ELeave) CHXAvCommand1_(*this);
    }
private:
    ClassType* m_pObject;
    PCMFN m_pMethod;
    ArgType m_arg;
};

//
// class CHXAvCommand0
//
// call to member func that takes no args, no return val
template< typename ClassType>
class CHXAvCommand0 : public CHXAvCommand
{
public:
    typedef void (ClassType::*PCMFN)();

    CHXAvCommand0(ClassType* pObject, PCMFN pMethod) 
        : m_pObject(pObject), m_pMethod(pMethod) {}

    void Execute()
    {
        (m_pObject->*m_pMethod)();
    }
    CHXAvCommand* CloneL() const 
    {
        return new (ELeave) CHXAvCommand0(*this);
    }
private:
    ClassType* m_pObject;
    PCMFN m_pMethod;
};

//
// class CHXAvCommand1
//
// call to member func that takes one arg, no return val
template< typename ClassType, typename ArgType >
class CHXAvCommand1 : public CHXAvCommand
{
public:
    typedef void (ClassType::*PCMFN)(ArgType arg);

    CHXAvCommand1(ClassType* pObject, PCMFN pMethod, ArgType arg) 
	    : m_pObject(pObject), m_pMethod(pMethod), m_arg(arg) {}

    void Execute()
    {
        (m_pObject->*m_pMethod)(m_arg);
    }
    CHXAvCommand* CloneL() const
    {
        return new (ELeave) CHXAvCommand1(*this);
    }
private:
    ClassType* m_pObject;
    PCMFN m_pMethod;
    ArgType m_arg;
};


//
// convenience helpers
//
// these save a few keystrokes (so you don't have to explicity
// type out template args) and enhance readability
//
// MakeCommand(pMyClass, &MyClass::Dance, value)
//
// vs.
//
// CHXAvCommand0<MyClass, int>(pMyClass, &MyClass::Dance, value);
//
// *** note use of long-hand for handling void return; we assume recent C++ 
// features (partial specializations, member fun templates, return void) 
// not likely to be supported

//
// *** with return value ***
//
template< typename ClassType, typename ReturnType >
inline
CHXAvCommand0_ <ClassType, ReturnType> 
MakeCommand_(  ClassType* pClass, ReturnType (ClassType::*pcmfn)() )
{
    return CHXAvCommand0_<ClassType, ReturnType>(pClass, pcmfn);
}

template< typename ClassType, typename ReturnType, typename ArgType>
inline
CHXAvCommand1_<ClassType, ReturnType, ArgType> 
MakeCommand_(  ClassType* pClass, ReturnType (ClassType::*pcmfn)(ArgType), ArgType arg )
{
    return CHXAvCommand1_<ClassType, ReturnType, ArgType>(pClass, pcmfn, arg);
}

template< typename ClassType, typename ReturnType >
inline
CHXAvCommand0_ <ClassType, ReturnType> *
AllocCommandL_(  ClassType* pClass, ReturnType (ClassType::*pcmfn)() )
{
    return new CHXAvCommand0_<ClassType, ReturnType>(pClass, pcmfn);
}

template< typename ClassType, typename ReturnType, typename ArgType>
inline
CHXAvCommand1_<ClassType, ReturnType, ArgType> *
AllocCommandL_(  ClassType* pClass, ReturnType (ClassType::*pcmfn)(ArgType), ArgType arg )
{
    return new CHXAvCommand1_<ClassType, ReturnType, ArgType>(pClass, pcmfn, arg);
}

//
// *** no return (void) ***
//
template< typename ClassType>
inline
CHXAvCommand0 <ClassType> 
MakeCommand(  ClassType* pClass, void (ClassType::*pcmfn)() )
{
    return CHXAvCommand0<ClassType>(pClass, pcmfn);
}

template< typename ClassType,  typename ArgType>
inline
CHXAvCommand1<ClassType, ArgType> 
MakeCommand(  ClassType* pClass, void (ClassType::*pcmfn)(ArgType), ArgType arg )
{
    return CHXAvCommand1<ClassType, ArgType>(pClass, pcmfn, arg);
}

template< typename ClassType>
inline
CHXAvCommand0 <ClassType> *
AllocCommandL(  ClassType* pClass, void (ClassType::*pcmfn)() )
{
    return new (ELeave) CHXAvCommand0<ClassType>(pClass, pcmfn);
}

template< typename ClassType,  typename ArgType>
inline
CHXAvCommand1<ClassType, ArgType> *
AllocCommandL(  ClassType* pClass, void (ClassType::*pcmfn)(ArgType), ArgType arg )
{
    return new (ELeave) CHXAvCommand1<ClassType, ArgType>(pClass, pcmfn, arg);
}


#endif // _chxavcommand_h_